More features and progress

1 files changed, 557 insertions, 0 deletions

diff --git a/types.c b/types.c
new file mode 100644
index 00000000..aa977507
--- /dev/null
+++ b/types.c
@@ -0,0 +1,557 @@
+// Logic for handling type_t types
+#include <gc/cord.h>
+#include <stdint.h>
+#include <limits.h>
+#include <math.h>
+
+#include "builtins/table.h"
+#include "types.h"
+#include "util.h"
+
+static CORD type_to_cord(type_t *t) {
+    switch (t->tag) {
+        case UnknownType: return "???";
+        case AbortType: return "Abort";
+        case VoidType: return "Void";
+        case MemoryType: return "Memory";
+        case BoolType: return "Bool";
+        case CharType: return "Char";
+        case IntType: return CORD_asprintf("Int%ld", Match(t, IntType)->bits);
+        case NumType: return CORD_asprintf("Num%ld", Match(t, NumType)->bits);
+        case ArrayType: {
+            auto array = Match(t, ArrayType);
+            return CORD_asprintf("[%r]", type_to_cord(array->item_type));
+        }
+        case TableType: {
+            auto table = Match(t, TableType);
+            return CORD_asprintf("{%r=>%r}", type_to_cord(table->key_type), type_to_cord(table->value_type));
+        }
+        case FunctionType: {
+            CORD c = "func(";
+            auto fn = Match(t, FunctionType);
+            for (arg_t *arg = fn->args; arg; arg = arg->next) {
+                c = CORD_cat(c, type_to_cord(arg->type));
+                if (arg->next) c = CORD_cat(c, ", ");
+            }
+            c = CORD_cat(c, ")->");
+            c = CORD_cat(c, type_to_cord(fn->ret));
+            return c;
+        }
+        case StructType: {
+            auto struct_ = Match(t, StructType);
+            CORD c = "struct(";
+            int64_t i = 1;
+            for (arg_t *field = struct_->fields; field; field = field->next) {
+                const char *fname = field->name ? field->name : heap_strf("_%lu", i);
+                ++i;
+                if (fname && !streq(fname, heap_strf("_%lu", i+1)))
+                    c = CORD_cat(CORD_cat(c, fname), ":");
+                else
+                    c = CORD_cat(c, ":");
+
+                c = CORD_cat(c, type_to_cord(field->type));
+
+                if (field->next) c = CORD_cat(c, ", ");
+            }
+            c = CORD_cat(c, ")");
+            return c;
+        }
+        case PointerType: {
+            auto ptr = Match(t, PointerType);
+            CORD sigil = ptr->is_stack ? "&" : (ptr->is_optional ? "?" : "@");
+            if (ptr->is_readonly) sigil = CORD_cat(sigil, "(readonly)");
+            return CORD_cat(sigil, type_to_cord(ptr->pointed));
+        }
+        case EnumType: {
+            auto tagged = Match(t, EnumType);
+
+            CORD c = "enum(";
+            int64_t next_tag = 0;
+            for (tag_t *tag = tagged->tags; tag; tag = tag->next) {
+                // name, tag_value, type
+                c = CORD_cat(c, tag->name);
+                if (tag->type) {
+                    c = CORD_cat(c, "(");
+                    auto struct_ = Match(tag->type, StructType);
+                    int64_t i = 1;
+                    for (arg_t *field = struct_->fields; field; field = field->next) {
+                        if (field->name && !streq(field->name, heap_strf("_%lu", i)))
+                            c = CORD_cat(CORD_cat(c, field->name), ":");
+
+                        CORD fstr = type_to_cord(field->type);
+                        c = CORD_cat(c, fstr);
+                        if (field->next) c = CORD_cat(c, ",");
+                        ++i;
+                    }
+                    c = CORD_cat(c, ")");
+                }
+
+                if (tag->tag_value != next_tag) {
+                    CORD_sprintf(&c, "%r=%ld", c, tag->tag_value);
+                    next_tag = tag->tag_value + 1;
+                } else {
+                    ++next_tag;
+                }
+
+                if (tag->next)
+                    c = CORD_cat(c, "|");
+            }
+            c = CORD_cat(c, ")");
+            return c;
+        }
+        case VariantType: {
+            return Match(t, VariantType)->name;
+        }
+        case PlaceholderType: {
+            return Match(t, PlaceholderType)->name;
+        }
+        case TypeInfoType: {
+            return "TypeInfo";
+        }
+        default: {
+            return CORD_asprintf("Unknown type: %d", t->tag);
+        }
+    }
+}
+
+int printf_pointer_size(const struct printf_info *info, size_t n, int argtypes[n], int sizes[n])
+{
+    if (n < 1) return -1;
+    (void)info;
+    argtypes[0] = PA_POINTER;
+    sizes[0] = sizeof(void*);
+    return 1;
+}
+
+int printf_type(FILE *stream, const struct printf_info *info, const void *const args[])
+{
+    (void)info;
+    type_t *t = *(type_t**)args[0];
+    if (!t) return fputs("(null)", stream);
+    return CORD_put(type_to_cord(t), stream);
+}
+
+const char *type_to_string(type_t *t) {
+    return CORD_to_const_char_star(type_to_cord(t));
+}
+
+bool type_eq(type_t *a, type_t *b)
+{
+    if (a == b) return true;
+    if (a->tag != b->tag) return false;
+    if (a->tag == PlaceholderType) return a == b;
+    return streq(type_to_string(a), type_to_string(b));
+}
+
+bool type_is_a(type_t *t, type_t *req)
+{
+    if (type_eq(t, req)) return true;
+    if (t->tag == PointerType && req->tag == PointerType) {
+        auto t_ptr = Match(t, PointerType);
+        auto req_ptr = Match(req, PointerType);
+        if (type_eq(t_ptr->pointed, req_ptr->pointed))
+            return (!t_ptr->is_stack && !t_ptr->is_optional && req_ptr->is_stack)
+                || (!t_ptr->is_stack && req_ptr->is_optional);
+    }
+    return false;
+}
+
+static type_t *non_optional(type_t *t)
+{
+    if (t->tag != PointerType) return t;
+    auto ptr = Match(t, PointerType);
+    return ptr->is_optional ? Type(PointerType, .is_optional=false, .pointed=ptr->pointed) : t;
+}
+
+type_t *value_type(type_t *t)
+{
+    while (t->tag == PointerType)
+        t = Match(t, PointerType)->pointed;
+    return t;
+}
+
+type_t *base_value_type(type_t *t)
+{
+    for (;;) {
+        if (t->tag == PointerType)
+            t = Match(t, PointerType)->pointed;
+        else if (t->tag == VariantType)
+            t = Match(t, VariantType)->variant_of;
+        else break;
+    }
+    return t;
+}
+
+type_t *type_or_type(type_t *a, type_t *b)
+{
+    if (!a) return b;
+    if (!b) return a;
+    if (type_is_a(b, a)) return a;
+    if (type_is_a(a, b)) return b;
+    if (a->tag == AbortType) return non_optional(b);
+    if (b->tag == AbortType) return non_optional(a);
+    if ((a->tag == IntType || a->tag == NumType) && (b->tag == IntType || b->tag == NumType)) {
+        switch (compare_precision(a, b)) {
+        case NUM_PRECISION_EQUAL: case NUM_PRECISION_MORE: return a;
+        case NUM_PRECISION_LESS: return b;
+        case NUM_PRECISION_INCOMPARABLE: {
+            if (a->tag == IntType && b->tag == IntType && Match(a, IntType)->bits < 64)
+                return Type(IntType, .bits=Match(a, IntType)->bits * 2);
+            return NULL;
+        }
+        }
+        return NULL;
+    }
+    return NULL;
+}
+
+bool is_integral(type_t *t)
+{
+    t = base_variant(t);
+    return t->tag == IntType || t->tag == CharType;
+}
+
+bool is_floating_point(type_t *t)
+{
+    t = base_variant(t);
+    return t->tag == NumType;
+}
+
+bool is_numeric(type_t *t)
+{
+    t = base_variant(t);
+    return t->tag == IntType || t->tag == NumType;
+}
+
+static inline double type_min_magnitude(type_t *t)
+{
+    switch (t->tag) {
+    case BoolType: return (double)false;
+    case CharType: return (double)CHAR_MIN;
+    case IntType: {
+        switch (Match(t, IntType)->bits) {
+        case 8: return (double)INT8_MIN;
+        case 16: return (double)INT16_MIN;
+        case 32: return (double)INT32_MIN;
+        case 64: return (double)INT64_MIN;
+        default: return NAN;
+        }
+    }
+    case NumType: return -1./0.;
+    case VariantType: return type_min_magnitude(Match(t, VariantType)->variant_of);
+    default: return NAN;
+    }
+}
+
+static inline double type_max_magnitude(type_t *t)
+{
+    switch (t->tag) {
+    case BoolType: return (double)true;
+    case CharType: return (double)CHAR_MAX;
+    case IntType: {
+        switch (Match(t, IntType)->bits) {
+        case 8: return (double)INT8_MAX;
+        case 16: return (double)INT16_MAX;
+        case 32: return (double)INT32_MAX;
+        case 64: return (double)INT64_MAX;
+        default: return NAN;
+        }
+    }
+    case NumType: return 1./0.;
+    case VariantType: return type_max_magnitude(Match(t, VariantType)->variant_of);
+    default: return NAN;
+    }
+}
+
+precision_cmp_e compare_precision(type_t *a, type_t *b)
+{
+    double a_min = type_min_magnitude(a),
+           b_min = type_min_magnitude(b),
+           a_max = type_max_magnitude(a),
+           b_max = type_max_magnitude(b);
+
+    if (isnan(a_min) || isnan(b_min) || isnan(a_max) || isnan(b_max))
+        return NUM_PRECISION_INCOMPARABLE;
+    else if (a_min == b_min && a_max == b_max) return NUM_PRECISION_EQUAL;
+    else if (a_min <= b_min && b_max <= a_max) return NUM_PRECISION_MORE;
+    else if (b_min <= a_min && a_max <= b_max) return NUM_PRECISION_LESS;
+    else return NUM_PRECISION_INCOMPARABLE;
+}
+
+bool is_orderable(type_t *t)
+{
+    switch (t->tag) {
+    case ArrayType: return is_orderable(Match(t, ArrayType)->item_type);
+    case PointerType: case FunctionType: case TableType: return false;
+    case StructType: {
+        for (arg_t *field = Match(t, StructType)->fields; field; field = field->next) {
+            if (!is_orderable(field->type))
+                return false;
+        }
+        return true;
+    }
+    case EnumType: {
+        for (tag_t *tag = Match(t, EnumType)->tags; tag; tag = tag->next) {
+            if (tag->type && !is_orderable(tag->type))
+                return false;
+        }
+        return true;
+    }
+    default: return true;
+    }
+}
+
+bool has_heap_memory(type_t *t)
+{
+    switch (t->tag) {
+    case ArrayType: return true;
+    case TableType: return true;
+    case PointerType: return true;
+    case StructType: {
+        for (arg_t *field = Match(t, StructType)->fields; field; field = field->next) {
+            if (has_heap_memory(field->type))
+                return true;
+        }
+        return false;
+    }
+    case EnumType: {
+        for (tag_t *tag = Match(t, EnumType)->tags; tag; tag = tag->next) {
+            if (tag->type && has_heap_memory(tag->type))
+                return true;
+        }
+        return false;
+    }
+    default: return false;
+    }
+}
+
+bool has_stack_memory(type_t *t)
+{
+    switch (t->tag) {
+    case PointerType: return Match(t, PointerType)->is_stack;
+    default: return false;
+    }
+}
+
+bool can_promote(type_t *actual, type_t *needed)
+{
+    // No promotion necessary:
+    if (type_eq(actual, needed))
+        return true;
+
+    if (is_numeric(actual) && is_numeric(needed)) {
+        auto cmp = compare_precision(actual, needed);
+        return cmp == NUM_PRECISION_EQUAL || cmp == NUM_PRECISION_LESS;
+    }
+
+    // Automatic dereferencing:
+    if (actual->tag == PointerType && !Match(actual, PointerType)->is_optional
+        && can_promote(Match(actual, PointerType)->pointed, needed))
+        return true;
+
+    // Optional promotion:
+    if (needed->tag == PointerType && actual->tag == PointerType) {
+        auto needed_ptr = Match(needed, PointerType);
+        auto actual_ptr = Match(actual, PointerType);
+        if (needed_ptr->pointed->tag != MemoryType && !type_eq(needed_ptr->pointed, actual_ptr->pointed))
+            // Can't use @Foo for a function that wants @Baz
+            // But you *can* use @Foo for a function that wants @Memory
+            return false;
+        else if (actual_ptr->is_stack && !needed_ptr->is_stack)
+            // Can't use &x for a function that wants a @Foo or ?Foo
+            return false;
+        else if (actual_ptr->is_optional && !needed_ptr->is_optional)
+            // Can't use !Foo for a function that wants @Foo
+            return false;
+        else if (actual_ptr->is_readonly && !needed_ptr->is_readonly)
+            // Can't use pointer to readonly data when we need a pointer that can write to the data
+            return false;
+        else
+            return true;
+    }
+
+    // Function promotion:
+    if (needed->tag == FunctionType && actual->tag == FunctionType) {
+        auto needed_fn = Match(needed, FunctionType);
+        auto actual_fn = Match(actual, FunctionType);
+        for (arg_t *needed_arg = needed_fn->args, *actual_arg = actual_fn->args;
+             needed_arg || actual_arg;
+             needed_arg = needed_arg->next, actual_arg = actual_arg->next) {
+
+            if (!needed_arg || !actual_arg)
+                return false;
+
+            if (!type_eq(needed_arg->type, actual_arg->type))
+                return false;
+        }
+        return true;
+    }
+
+    // If we have a DSL, it should be possible to use it as a Str
+    if (is_variant_of(actual, needed))
+        return true;
+
+    if (actual->tag == StructType && base_variant(needed)->tag == StructType) {
+        auto actual_struct = Match(actual, StructType);
+        auto needed_struct = Match(base_variant(needed), StructType);
+        // TODO: allow promoting with uninitialized or extraneous values?
+        for (arg_t *needed_field = needed_struct->fields, *actual_field = actual_struct->fields;
+             needed_field || actual_field;
+             needed_field = needed_field->next, actual_field = actual_field->next) {
+
+            if (!needed_field || !actual_field)
+                return false;
+
+            // TODO: check field names??
+            if (!can_promote(actual_field->type, needed_field->type))
+                return false;
+        }
+        return true;
+    }
+
+    return false;
+}
+
+bool can_leave_uninitialized(type_t *t)
+{
+    switch (t->tag) {
+    case PointerType: return Match(t, PointerType)->is_optional;
+    case ArrayType: case IntType: case NumType: case CharType: case BoolType:
+        return true;
+    case StructType: {
+        for (arg_t *field = Match(t, StructType)->fields; field; field = field->next) {
+            if (!can_leave_uninitialized(field->type))
+                return false;
+        }
+        return true;
+    }
+    case EnumType: {
+        for (tag_t *tag = Match(t, EnumType)->tags; tag; tag = tag->next) {
+            if (tag->type && !can_leave_uninitialized(tag->type))
+                return false;
+        }
+        return true;
+    }
+    default: return false;
+    }
+}
+
+static bool _can_have_cycles(type_t *t, table_t *seen)
+{
+    switch (t->tag) {
+        case ArrayType: return _can_have_cycles(Match(t, ArrayType)->item_type, seen);
+        case TableType: {
+            auto table = Match(t, TableType);
+            return _can_have_cycles(table->key_type, seen) || _can_have_cycles(table->value_type, seen);
+        }
+        case StructType: {
+            for (arg_t *field = Match(t, StructType)->fields; field; field = field->next) {
+                if (_can_have_cycles(field->type, seen))
+                    return true;
+            }
+            return false;
+        }
+        case PointerType: return _can_have_cycles(Match(t, PointerType)->pointed, seen);
+        case EnumType: {
+            for (tag_t *tag = Match(t, EnumType)->tags; tag; tag = tag->next) {
+                if (tag->type && _can_have_cycles(tag->type, seen))
+                    return true;
+            }
+            return false;
+        }
+        case VariantType: {
+            const char *name = Match(t, VariantType)->name;
+            if (name && Table_str_get(seen, name))
+                return true;
+            Table_str_set(seen, name, t);
+            return _can_have_cycles(Match(t, VariantType)->variant_of, seen);
+        }
+        default: return false;
+    }
+}
+
+bool can_have_cycles(type_t *t)
+{
+    table_t seen = {0};
+    return _can_have_cycles(t, &seen);
+}
+
+type_t *table_entry_type(type_t *table_type)
+{
+    static table_t cache = {0};
+    arg_t *fields = new(
+        arg_t, .name="key",
+        .type=Match(table_type, TableType)->key_type);
+    fields->next = new(
+        arg_t, .name="value",
+        .type=Match(table_type, TableType)->value_type);
+    type_t *t = Type(StructType, .fields=fields);
+    type_t *cached = Table_str_get(&cache, type_to_string(t));
+    if (cached) {
+        return cached;
+    } else {
+        Table_str_set(&cache, type_to_string(t), t);
+        return t;
+    }
+}
+
+type_t *base_variant(type_t *t)
+{
+    while (t->tag == VariantType)
+        t = Match(t, VariantType)->variant_of;
+    return t;
+}
+
+bool is_variant_of(type_t *t, type_t *base)
+{
+    for (; t->tag == VariantType; t = Match(t, VariantType)->variant_of) {
+        if (type_eq(Match(t, VariantType)->variant_of, base))
+            return true;
+    }
+    return false;
+}
+
+type_t *replace_type(type_t *t, type_t *target, type_t *replacement)
+{
+    if (type_eq(t, target))
+        return replacement;
+
+#define COPY(t) memcpy(GC_MALLOC(sizeof(type_t)), (t), sizeof(type_t))
+#define REPLACED_MEMBER(t, tag, member) ({ t = memcpy(GC_MALLOC(sizeof(type_t)), (t), sizeof(type_t)); Match((struct type_s*)(t), tag)->member = replace_type(Match((t), tag)->member, target, replacement); t; })
+    switch (t->tag) {
+        case ArrayType: return REPLACED_MEMBER(t, ArrayType, item_type);
+        case TableType: {
+            t = REPLACED_MEMBER(t, TableType, key_type);
+            t = REPLACED_MEMBER(t, TableType, value_type);
+            return t;
+        }
+        case FunctionType: {
+            auto fn = Match(t, FunctionType);
+            t = REPLACED_MEMBER(t, FunctionType, ret);
+            arg_t *args = LIST_MAP(fn->args, old_arg, .type=replace_type(old_arg->type, target, replacement));
+            Match((struct type_s*)t, FunctionType)->args = args;
+            return t;
+        }
+        case StructType: {
+            auto struct_ = Match(t, StructType);
+            arg_t *fields = LIST_MAP(struct_->fields, field, .type=replace_type(field->type, target, replacement));
+            t = COPY(t);
+            Match((struct type_s*)t, StructType)->fields = fields;
+            return t;
+        }
+        case PointerType: return REPLACED_MEMBER(t, PointerType, pointed);
+        case EnumType: {
+            auto tagged = Match(t, EnumType);
+            tag_t *tags = LIST_MAP(tagged->tags, tag, .type=replace_type(tag->type, target, replacement));
+            t = COPY(t);
+            Match((struct type_s*)t, EnumType)->tags = tags;
+            return t;
+        }
+        case VariantType: return REPLACED_MEMBER(t, VariantType, variant_of);
+        default: return t;
+    }
+#undef COPY
+#undef REPLACED_MEMBER
+}
+
+// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0